During the 3 1/2 years since it was first funded by NIH, the Center for Fast Kinetics Research (CFKR) has assembled a unique combination of technical capabilities for the production and analysis of fast transients (ns and longer). A 5 MeV Van de Graaff accelerator produces electron pulses for pulse radiolysis. A pulsed nitrogen laser provides photon pulses for flash photolysis, and this capability is being extended into the sub-ns region by the purchase of a Nd:glass laser system. Several techniques for transient detection are provided, including optical emission and absorption spectroscopy, conductivity, and polarography. Stopped-flow fast mixing and steady-state spectrofluorimetry are also available. All systems are computerized so that immediate readout is available during the experiment, allowing quick analysis and change of experimental conditions and saving the researchers countless hours of post-experiment data reduction. These experimental capabilities, together with the personal services of the CFKR staff, are made available to biological and biomedical researchers (currently 50) throughout the nation. Fast kinetic techniques are of wide applicability in the biological sciences, encompassing such diverse research areas as the mechanism of chemical radiation sensitization of tumors, time-resolved fluorescence depolarization studies of biological membrane structure and function, the photophysics and photochemistry of visual pigments, the O2 effect in irradiated cells, measurement of the degree of drug-protein binding, and many others. The CFKR is continually seeking to develop new fast kinetic techniques and to apply existing ones to new problems of biomedical interest; to undertake interdisciplinary collaboration with outside researchers in promising new fields; to serve a wider group of users composed primarily of biological scientists who wish to apply fast kinetic techniques to their areas of research interest; to train fast kineticists who can bridge the gap between rapidly advancing instrumental technology and the biological problems to which it should be applied; and to publicize both the results of these endeavors and the potential for further advancement in the application of these methods.